Suppose a rocket launches with an acceleration of 39 m/s2. What is the apparent weight of an 90 kg astronaut aboard this rocket?
Suppose that a binary star system consists of two stars of equal mass. They are observed to be separated by 330 million kilometers and take 3.0 Earth years to orbit about a point midway between them. What is the mass of each?
How do I know which one is a plant and which one is a plant cell.